A method for reducing the slag adhering layer in a submerged arc furnace

Abstract

The present invention discloses a method for reducing the slag adhering layer in a settling electric furnace, which includes: (1) separately preparing reducing agents A, B, and C; (2) in an electric furnace during normal production, measuring the thickness h of the slag adhering layer with a sampling rod at the furnace top, sending the upper slag and middle adhering slag suspended on the sampling rod to a laboratory for chemical analysis, selecting a corresponding reducing agent according to the thickness h of the slag adhering layer and the chemical compositions of the slag and adhering slag, and putting the reducing agent into the molten bath from the observation hole and feed inlet at the top of the electric furnace. The reducing agent directly falls into the adhering slag layer between the slag layer and matte to reduce and impoverish the adhering slag, and controlling the reduction of the adhering slag layer within 0 - 200 mm. The present invention can effectively reduce the content of magnetic iron in the melt of the settling electric furnace, convert the oxides of Cu, Ni, and Co into matte, and inhibit the adhesion of magnetic iron and the oxides of Cu, Ni, and Co to form furnace knots at the furnace bottom.

Description

Technical Field

[0001] The invention relates to the technical field of nonferrous metal smelting, and more particularly to a method for reducing a sticky slag layer in a sedimentation electric furnace. Background Art

[0002] The copper concentrate is sent to the top-blown furnace for matte smelting. The slag and matte (matte) mixture produced by smelting under strong oxygen potential is sent to the sedimentation furnace for slag and matte sedimentation separation. A layer of sticky slag will form between the slag layer and the matte layer. This layer of sticky slag is usually Fe 3 O 4 , MgO, and Cu content are very high. If this layer of sticky slag cannot be effectively controlled, it is easy to cause the slag magnetism to increase, the viscosity to increase, the slag copper content to be high, and the slag matte sedimentation and separation effect to be poor; the sticky slag adheres to the bottom of the furnace to form a furnace knot, reducing the effective volume space of the electric furnace; the slag and matte are not discharged smoothly and other vicious consequences; the sticky slag layer cannot be effectively controlled, which makes copper smelting enterprises miserable. Improper or untimely disposal will cause the smelting furnace to stop, and even cause foam slag accidents. The peers have the method of spraying reducing agent, flux + stirring to reduce and enrich the electric furnace slag, but the electric furnace does not have a wide enough volume space to meet the requirements of melt expansion, and the furnace top is prone to coking; the peers also put pig iron and solid reducing agent into the furnace for reduction and enrichment, but the reducing agent either sinks to the bottom of the furnace or floats on the surface of the molten pool, and it is impossible to do efficient reduction and enrichment of the highly magnetic sticky slag, and it is even more unsatisfactory when encountering slag with high MgO content.

[0003] Therefore, how to safely and efficiently eliminate the hazards caused by sticky slag in electric furnaces is the focus and technical challenge of modern copper metallurgy. Summary of the invention

[0004] In view of this, the present invention provides a method for reducing the sticky slag layer of the electric furnace to solve the deficiencies in the prior art. The method can quickly and effectively reduce the sticky slag layer, inhibit the growth of the frozen layer at the bottom of the furnace, improve the slag and matte sedimentation and separation effect and discharge fluidity, thereby optimizing the copper pyrometallurgical smelting process.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A method for reducing and settling a sticky slag layer in an electric furnace comprises the following steps:

[0007] (1) Mix carbon powder, quartz powder, pyrite powder, and copper matte powder in a mass ratio of 4:1:1:mA and add 10% water, send it to a roller pelletizer to press it into a granular reducing agent A with a diameter of Φ=4-8mm, air-dry it and bag it for later use; Mix carbon powder, pyrite powder, and copper matte powder in a mass ratio of 4:1:mB and add 10% water, send it to a roller pelletizer to press it into a granular reducing agent B with a diameter of Φ=4-8mm, air-dry it and bag it for later use; Mix carbon powder, quartz powder, and copper matte powder in a mass ratio of 4:1:mC and add 10% water, send it to a roller pelletizer to press it into a granular reducing agent C with a diameter of Φ=4-8mm, air-dry it and bag it for later use;

[0008] (2) For an electric furnace in normal production, use a sampling rod on the furnace top to measure the thickness h of the sticky slag layer, and send the upper slag and middle sticky slag hanging on the sampling rod to the laboratory for analysis (the sampling rod needs to be left still for about 2 minutes after entering the molten pool, and the slag and sticky slag will adhere to the sampling rod in layers). According to the thickness h of the sticky slag layer and the chemical composition of the slag and sticky slag, select a suitable reducing agent, and put the reducing agent into the molten pool from the observation hole and the feed port on the top of the electric furnace. The reducing agent directly falls into the sticky slag layer between the slag layer and the matte to reduce and deplete the sticky slag, and control the reduction of the sticky slag layer to between 0 and 200 mm.

[0009] The four ingredients for preparing the reducing agent do not undergo chemical changes at room temperature and pressure. After the reducing agent is put into the electric furnace, the copper matte in the reducing agent melts at high temperature (the molten pool temperature in the furnace is 1240-1320°C, and the melting point of the copper matte is 950-1050°C), and then dissociates to release carbon, quartz, and pyrite to reduce and enrich the sticky slag of the electric furnace.

[0010] When the molten copper matte contacts the highly magnetic slag, a large amount of copper matte melts and sinks into the copper matte layer, while a small amount of copper matte and Fe 3 O 4 Interaction occurs:

[0011] Cu 2 S+3Fe 3 O 4 =Cu 2 O+9FeO+SO 2

[0012] FeS+3Fe 3 O 4 =10FeO+SO 2

[0013] The C released by dissociation reacts with Fe 3 O 4 To perform a strong restore:

[0014] C+Fe 3 O 4 =3FeO+CO

[0015] Fe3 O 4 +CO=3FeO+CO 2

[0016] Pyrite decomposition and reduction of Fe 3 O 4 , Cu 2 O, NiO, CoO matte is sunk into the matte layer:

[0017] 2FeS 2 =2FeS+S 2

[0018] S 2 +4Fe 3 O 4 =12FeO+2SO 2

[0019] FeS+Cu 2 O=Cu 2 S+FeO

[0020] 6NiO+6FeS=2Ni 3 S 2 +6FeO+S 2

[0021] CoO+FeS=CoS+FeO

[0022] FeS+Cu 2 S+Ni 3 S 2 +CoS→Matte

[0023] SiO released by ionization 2 Remove the FeO produced by the reduction reaction and the MgO in the sticky slag by slagging:

[0024] 2FeO+SiO 2 =2FeO·SiO 2 (Fayalite)

[0025] MgO+SiO 2 =MgO·SiO 2 (Forsterite)

[0026] For sticky slag with MgO content ≤ 1.6, control the slag to 1.2 ≤ FeO / SiO 2 ≤1.4; 3.5<CaO%≤6. When reducing the high MgO sticky slag layer, the CaO content of the slag discharged from the top-blown furnace needs to be controlled to 3-3.5%, which is equivalent to reducing the CaO content and using MgO to replace CaO to adjust the pH of the slag (top-blown furnace smelting copper concentrate uses FeO+SiO 2 +CaO ternary slag).

[0027] The carbon powder used to prepare the abatement agent is anthracite powder with a fixed carbon content of ≥90%; the quartz powder SiO 2 content>90%; the copper matte contains 55%<Cu<65%, 7%<Fe<15%, 14%<S<20%; the pyrite powder contains FeS>85%.

[0028] The prepared reducing agents of the present invention are: reducing agent A, reducing agent B, and reducing agent C; the specific gravity of the three reducing agents is greater than that of slag, less than that of matte, and similar to that of sticky slag. When reducing agent A is prepared, the mass ratio of carbon powder, quartz powder, and pyrite powder is 4:1:1. The specific gravity of reducing agent A is adjusted by adjusting the amount of copper matte powder added, m A The value is obtained by calculation; when the reducing agent B is configured, the mass ratio of carbon powder to pyrite powder is 4:1, and the specific gravity of the reducing agent B is adjusted by adjusting the amount of copper matte powder added, m B The value is obtained by calculation; when the reducing agent C is configured, the mass ratio of carbon powder to quartz powder is 4:1, and the specific gravity of the reducing agent C is adjusted by adjusting the amount of copper matte powder added, m C The value is obtained by calculation; the ratio of each component of the reducing agent A, B, and C can be adjusted in a small range according to production requirements.

[0029] The amount of copper matte powder added to the reducing agent A, B, C is m A 、m B 、m C The calculation formula is:

[0030]

[0031]

[0032]

[0033] The 碳 , 石英 , 硫铁矿 , 锍 is the standard specific gravity of anthracite, quartz, pyrite and copper matte, which is measured by a solid density measuring instrument before the material is crushed. 黏渣 is the specific gravity of the electric furnace slag, when calculating the ingredients, ρ 黏渣 The value is 4g / cm 3 It is appropriate.

[0034] The substances involved in the present invention are not pure substances, and the specific gravity of the same materials in different batches varies. In order to ensure that the prepared reducing agent can fall into the sticky slag layer, the specific gravity of the carbon powder, quartz powder, pyrite powder and copper matte used to prepare the reducing agent must be measured on site.

[0035] Anthracite specific gravity 1.4~1.6g / cm 3

[0036] Quartz sand specific gravity 2.2~2.7g / cm 3

[0037] Slag specific gravity 3.2~3.8g / cm 3

[0038] The specific gravity of sticky residue is 3.7~4.4g / cm 3

[0039] Matte specific gravity 4.7~5.5g / cm 3 , melting point 950~1050℃

[0040] Pyrite specific gravity 4.4~4.8g / cm 3 , melting point 1193℃

[0041] After the reducing agent is prepared, use a solid density meter to check its specific gravity, which must meet the following requirements: ρ 炉渣 <ρ 消减剂 =ρ 黏渣 <ρ 锍 ;

[0042] In order to improve the furnace condition of the electric furnace efficiently and safely, the thickness of the sticky slag layer and the composition of the sticky slag are different, and the type, frequency, amount and control parameters of the reducing agent are also different. The specific control is as described in the following table:

[0043]

[0044]

[0045] As described in the above operation control table:

[0046] 1. Whether the sedimentation furnace needs to be reduced is based on whether the thickness of the sticky slag exceeds 200mm. The thicker the sticky slag, the more the dosage of the reducing agent needs to be added. Sufficient temperature is required to quickly melt the reducing agent and enhance the reaction effect. Therefore, the thicker the sticky slag, the higher the operating temperature.

[0047] 2. When the MgO content of sticky slag is greater than 1.6%, the CaO content of the slag needs to be controlled at 3% to 3.5%, which is equivalent to reducing the CaO content and using MgO to replace CaO to adjust the pH of the slag (top-blown furnace smelting copper concentrate uses FeO+SiO 2 +CaO ternary slag).

[0048] 3. The reducing agent A contains carbon powder, quartz powder, pyrite powder and copper matte powder, which can quickly reduce the components in the sticky slag, make slag and matte, and the effect is more comprehensive, mainly for high Cu and high Fe 3 O 4, high MgO stubborn sticky slag.

[0049] 4. Reducer B lacks quartz powder compared to reducer A, and the slag-making effect is poor. After reducing the quartz powder, the proportion of carbon and pyrite increases, and the reduction of high Cu and high Fe 3 O 4 , low MgO slag sticking effect is better.

[0050] 5. Reducer C lacks pyrite compared to reducer A, and the matte-making effect is poor. After reducing pyrite, the proportion of carbon and quartz powder increases. 3 O 4 , low Cu slag sticking effect is better.

[0051] The present invention is used to reduce the sticky slag layer of a settling electric furnace. The time of adding the reducing agent should be staggered with the time of releasing the slag and the matte by more than half an hour to prevent the reducing agent added to the molten pool from being discharged from the molten pool along with the slag and matte without complete reaction.

[0052] The type, dosing frequency, addition amount, slag type control range and temperature control range of the reducing agent are adjusted once a day as the condition of the sedimentation furnace changes until the sticky slag reduction is controlled between 0 and 200 mm.

[0053] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0054] 1. The reducing agent in the present invention is directly added from the hole on the furnace top, without the need for a feeding device or a blowing device. There is no need to consider the problems of the feeding and blowing devices being difficult to maintain, the nozzles being easy to burn out, the insufficient expansion space for the melt during the blowing operation, and the coking on the furnace top. The operation and control are simpler and more practical.

[0055] 2. The specific gravity of the reducing agent is equivalent to that of the sticky slag. After being put into the electric furnace, it falls into the sticky slag layer. It not only reduces and enriches the sticky slag layer, but also reduces and enriches the slag during the descent process. The matte sinks and passes through the sticky slag layer and contacts the reducing agent in the sticky slag layer, which can reduce part of the Fe carried by the matte. 3 O 4 Reduce slag and improve the fluidity of copper matte.

[0056] 3. The top-blown furnace smelting copper concentrate is a strong oxygen potential molten pool smelting technology. The charge stays in the molten pool for a very short time, there is no sufficient slag making time, and the low Fe / SiO 2 Slag type control easily produces raw material (quartz stone has a melting point above 1300°C and exists in the form of raw material if slag cannot be quickly formed). Therefore, top-blown smelting cannot add enough flux required for slag formation. The reducer in the present invention contains quartz powder, which can supplement the slag forming flux and remove the reduced FeO and part of the high-melting-point MgO in the slag by slag forming.

[0057] 4. The Cu in the sedimentation electric furnace slag phase is mostly Cu 2 O, the pyrite entrained in the reducer decomposes to generate FeS, which can react with Cu 2 O is made into matte phase.

[0058] 5. The C powder carried by the reducing agent is a strong reducing agent, which can quickly reduce Fe 3 O 4 The slag layer can also be reduced by the upward movement of C and CO from the sticky slag layer. After oxidation, the C element is converted into CO. 2 The flue gas enters in the form of CO, so there is no CO hazard.

[0059] 6. The present invention can effectively reduce the magnetic iron content of the melt in the settling electric furnace, make Cu, Ni, and Co oxides into mattes, and inhibit the magnetic iron and Cu, Ni, and Co oxides from adhering to the furnace bottom to form furnace agglomerates. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0061] Figure 1 Operation flow chart of the present invention

[0062] Figure 2 This is a schematic diagram of the sampling rod of the present invention being inserted into the molten pool of an electric furnace;

[0063] Figure 3 This is a schematic diagram of slag hanging on the sampling rod of the present invention.

[0064] In the figure, 1-observation hole, 2-feeding port, 3-slag layer, 4-slag discharge port, 5-sticky slag layer, 6-matte layer, 7-furnace knot, 8-electrode, 9-sampling rod, 10-matte discharge port, 11-reducing agent, 12-sampling rod winch. DETAILED DESCRIPTION

[0065] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] Example 1

[0067] Taking the top-blown smelting furnace + settling furnace that processes 600,000 tons of copper concentrate annually as an example, the sampling rod is vertically inserted into the settling furnace until the sampling rod touches the furnace knot. After standing for 2 minutes, it is lifted out of the molten pool. The measured slag thickness h is 300mm. The sampling test results are:

[0068] Sticky residue: Fe 3 O 4 -21%, MgO-1.55%, Cu-0.78%

[0069] Slag: Fe / SiO 2 -1.33, CaO-3.6%

[0070] Measured slag temperature: 1275℃

[0071] Check the operation control table of reducing agent use, and add reducing agent according to the method described in the table: slag type and temperature do not need to be adjusted, and the reducing agent used is When no slag or matte is discharged, add 3 kg of reducing agent B and 3 kg of reducing agent C to each hole, 3 times a day.

[0072] At the same time on the second day, the sampling rod was vertically inserted into the sedimentation electric furnace until it touched the furnace. After standing for 2 minutes, it was lifted out of the molten pool. The thickness of the sticky slag h was measured to be 230 mm. The sampling test results were:

[0073] Sticky residue: Fe 3 O 4 -18%, MgO-1.51%, Cu-0.68%

[0074] Slag: Fe / SiO 2 -1.32, CaO-3.7%

[0075] Measured slag temperature: 1255℃

[0076] Check the operation control table of reducing agent use, and add reducing agent according to the method described in the table: the slag type does not need to be adjusted, increase the power of the electric furnace to raise the slag temperature to 1260-1300℃, and use reducing agent as follows: When no slag or matte is discharged, add 3 kg of reducing agent B and 3 kg of reducing agent C to each hole, 3 times a day.

[0077] At the same time on the third day, the sampling rod was vertically inserted into the sedimentation electric furnace until it touched the furnace knot. After standing for 2 minutes, it was lifted out of the molten pool. The slag thickness h was measured to be 160mm, and the slag reduction operation was completed.

[0078] Example 2

[0079] Taking the top-blown smelting furnace + settling furnace that processes 600,000 tons of copper concentrate annually as an example, the sampling rod is vertically inserted into the settling furnace until the sampling rod touches the furnace knot. After standing for 2 minutes, it is lifted out of the molten pool. The measured slag thickness h is 300mm. The sampling test results are:

[0080] Sticky residue: Fe 3 O 4 -23%, MgO-2.3%, Cu-1.88%

[0081] Slag: Fe / SiO 2 -1.32, CaO-3.9%

[0082] Measured slag temperature: 1265℃

[0083] Check the reduction agent operation control table and add the reduction agent according to the method described in the table: slag Fe / SiO 2 No adjustment is required. Reduce the amount of CaO added to the top-blown furnace, and the CaO content in the slag should be close to 3-3.5%. Increase the power of the electric furnace to raise the slag temperature to 1270-1310°C. Use reducing agent A. When not discharging slag or matte, add 8kg of reducing agent A to each hole, and add 5 times a day.

[0084] At the same time on the second day, the sampling rod was vertically inserted into the sedimentation electric furnace until it touched the furnace. After standing for 2 minutes, it was lifted out of the molten pool. The thickness of the sticky slag h was measured to be 280mm. The sampling test results were:

[0085] Sticky residue: Fe 3 O 4 -20.5%, MgO-1.94%, Cu-1.23%

[0086] Slag: Fe / SiO 2 -1.32, CaO-3.2%

[0087] Measured slag temperature: 1280℃

[0088] Check the operation control table for the use of reducing agents, and add reducing agents according to the method described in the table: the slag type and temperature do not need to be adjusted, and the reducing agent used is A. When no slag or matte is discharged, add 7.5 kg of reducing agent A to each hole, 3 times a day.

[0089] At the same time on the third day, the sampling rod was vertically inserted into the sedimentation electric furnace until the sampling rod touched the furnace knot. After standing for 2 minutes, it was lifted out of the molten pool. The measured slag thickness h was 220mm. The sampling and testing results were:.

[0090] Sticky residue: Fe 3 O 4 -19%, MgO-1.88%, Cu-0.78%

[0091] Slag: Fe / SiO 2 -1.36, CaO-3.3%

[0092] Measured slag temperature: 1285℃

[0093] Check the operation control table for the use of reducing agents, and add reducing agents according to the method described in the table: the slag type and temperature do not need to be adjusted, and the reducing agent used is C. When not discharging slag or matte, add 5.5 kg of C to each hole, and add 3 times a day.

[0094] At the same time on the fourth day, the sampling rod was vertically inserted into the sedimentation electric furnace until it touched the furnace knot. After standing for 2 minutes, it was lifted out of the molten pool. The slag thickness h was measured to be 185mm, and the slag reduction operation was completed.

[0095] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0096] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for reducing the slag adhering layer in a submerged arc furnace, characterized in that, it includes the following steps: (1) Mix carbon powder, quartz powder, pyrite powder, and copper matte powder with water to obtain reducing agent A for standby; mix carbon powder, pyrite powder, and copper matte powder with water to obtain reducing agent B for standby; mix carbon powder, quartz powder, and copper matte powder with water to obtain reducing agent C for standby; (2) In a submerged arc furnace during normal production, use a sampling rod at the furnace top to measure the thickness h of the slag adhering layer, and send the upper slag and middle adhering slag suspended on the sampling rod to the laboratory for chemical analysis. Select the corresponding reducing agent according to the thickness h of the slag adhering layer and the chemical components of the slag and adhering slag. Put the reducing agent into the molten bath from the observation hole and feed port at the furnace top. The reducing agent directly falls into the slag adhering layer between the slag layer and the copper matte to reduce and impoverish the adhering slag, and control the reduction of the slag adhering layer within 0 - 200 mm; The decontaminant A specifically is: Mix carbon powder, quartz powder, pyrite powder, and copper matte powder according to a mass ratio of 4:1:1:m A Add 10% water and mix evenly, then send it to a pair-roll granulator to press into granular decontaminant A with a diameter of Φ = 4 - 8 mm; The abatement agent B specifically is: mixing carbon powder, pyrite powder, and copper matte powder according to a mass ratio of 4:1:m B adding 10% water and mixing evenly, and sending it to a pair-roll granulator to granulate into abatement agent B in the shape of particles with a diameter of Φ = 4 - 8 mm; The abatement agent C specifically is: Mix carbon powder, quartz powder, and copper matte powder according to a mass ratio of 4:1:m C Add 10% water and mix evenly, then send it to a pair-roll granulator to press into granular abatement agent C with Φ = 4 - 8 mm; The said m A , m B , m C The calculation equation is as follows: The ρ carbon, ρ quartz, ρ pyrite, and ρ matte are the specific gravities of anthracite, quartz, pyrite, and copper matte under standard conditions, which are measured by a solid density measuring instrument for the materials before crushing. The ρ sticky slag is the specific gravity of the electric furnace sticky slag, with a value of 4 g / cm 3 .

2. The method for reducing the slag adhering layer in a submerged arc furnace according to claim 1, characterized in that, The toner is anthracite powder with a fixed carbon content of ≥90%; the quartz powder has an SiO 2 content of >90%; the copper matte has 55% < Cu < 65%, 7% < Fe < 15%, and 14% < S < 20%; the pyrite powder contains Fe > 30% and S > 33%.

3. The method for reducing the slag adhering layer in a submerged arc furnace according to claim 2, characterized in that, In step (2), the types, dosing frequencies, input amounts of the reducing agent added to the observation hole and feed port at the furnace top, as well as the slag type and slag temperature of the furnace slag are controlled as described in the following table:

4. The method for reducing the slag adhering layer in a submerged arc furnace according to claim 3, characterized in that, The dosing time of the reducing agent is staggered by more than 0.5 h before and after the slag tapping and copper matte tapping times.

5. The method for reducing the slag adhering layer in a submerged arc furnace according to claim 4, characterized in that, The types, dosing frequencies, addition amounts, slag type control range, and temperature control range of the reducing agent are adjusted once a day according to the changes in the conditions of the submerged arc furnace until the reduction of the adhering slag is controlled within 0 - 200 mm.

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